340 cylinder head bolts need washers?

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jabdusty57

jabdusty57

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My 340 overheated and one of the heads warped. The machine shop says its because whoever put the engine together the last time didn't use lock washers on the head bolts. They said they could tell because the bolts dug groves into the head. Does this make sense? The ARP replacement bolts I ordered didn't come with washers either. My repair manual doesn't appear to show or make reference to head bolt washers.

These are the original bolts.
 

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No. The stock bolts don't have lock washers.

They're blowing smoke up your a$$....
 
Find another machine shop!

*OEM come without washers.
*Correct flat washers can be used to help spread the load and get the bolts torqued more accurately.
*No such thing as "lock" washers for cylinder head bolts. Proper torque is used to keep everything right. Some recommend retorquing the head bolts after warm-up.
* Do not use Lock-tite on head bolts. Only lube and torque to specs based on the lube used.
 
Locomotion said:
Find another machine shop!

*OEM come without washers.
*Correct flat washers can be used to help spread the load and get the bolts torqued more accurately.
*No such thing as "lock" washers for cylinder head bolts. Proper torque is used to keep everything right. Some recommend retorquing the head bolts after warm-up.
* Do not use Lock-tite on head bolts. Only lube and torque to specs based on the lube used.
Click to expand...

Ok - so I should use ARP Ultra Torque Assembly lube?
 
Ok - so I should use ARP Ultra Torque Assembly lube?
Click to expand...

Yes, or something similar, just make sure when using preload lube, you're using it consistently...moly or ARP assembly lube will require a different torque spec than something like 30 weight motor oil. It's your engine, but I wouldn't recommend installing any high stress fasteners dry.
 
....and torque them down in steps (i.e.: 20-40-60-etc.) and recommended pattern. There should be some of that info with the bolts or possibly on the ARP website.
 
Use caution when lubing bolts. the torque specs were developed for the bolts as they came from the "factory", not with additional lube. Any extra lube will cause you to overtorque the bolts.

I would chase the bolts and block threads with a tap and die and at most put a little motor oil on them and then torque to service manual specs.
 
Years ago I had a problem with the ARP head bolts.
The set I had came with washers but I couldn't use the washers cause there wouldn't be enough thread engagement. The ARP bolts were shorter than the stock head bolts.
 
Id grab my parts and go to another machine shop. Stock bolts have no washers.
 
I don't think that the counterbores for the head bolts will accept too many styles of washers anyhow. they are pretty narrow for the standard 1/2" grade 8 flat washer.
 
Not only do Mopar bolts NOT come with any washers, I don't know of ANY iron head engine that does, unless maybe some oddball that uses studs. Certainly NOT lock washers.
 
krazykuda said:
Use caution when lubing bolts. the torque specs were developed for the bolts as they came from the "factory", not with additional lube. Any extra lube will cause you to overtorque the bolts.

I would chase the bolts and block threads with a tap and die and at most put a little motor oil on them and then torque to service manual specs.
Click to expand...

krazykuda is right. The factory spec is for clean, lightly oiled threads. Using ARP lube reduces the friction and requires you to drop the torque spec down, but by how much? Who knows? Just use good quality oil on clean threads. I've torqued hundreds of head bolts with just oil and never had a problem.

Also, remember to put a couple of drops of oil underneath the bolt head where it rubs on the head.
 
lilcuda said:
krazykuda is right. The factory spec is for clean, lightly oiled threads. Using ARP lube reduces the friction and requires you to drop the torque spec down, but by how much? Who knows? Just use good quality oil on clean threads. I've torqued hundreds of head bolts with just oil and never had a problem.

Also, remember to put a couple of drops of oil underneath the bolt head where it rubs on the head.
Click to expand...

Scratch that. I just re-read your post and noticed that you have ARP replacement bolts. If you use those, then follow ARP's instructions, use their lube and you'll be good to go.
 
hi, If you use moly lube, you can use 10 # less torque on head bolts. you will have same clamping effect, yet less distortion on block. on my 340, I use 80# with moly lube. there is way less distortion, bores are straighter. as for problems, =none.at 95 # it will bell mouth the bores. just food for thought.
 
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